Recent research and theorizing emphasize the role of the practitioner's affective behavior as a primary determinant of patients' perceptions of the efficacy of treatment, and of their satisfaction with treatment. Moreover, the practitioner's affective behavior is believed to be a major factor in influencing patients to engage in preventive health behavior. Two components of student-dentists' affective behavior are differentiated. One is their ability to decode and encode nonverbal, affective behavior. The second is the nature and extent of the affective behavior which they exhibit during patient interaction. It is hypothesized that these two components have an additive effect on patient satisfaction. The hypothesis will be tested in a two-year investigation in which measures of nonverbal, paraverbal, and verbal behavior will be coded from videotaped segments of patient/student-dentist interaction. The student-dentists will also complete tests of their skills in decoding and encoding nonverbal communication. Self-report measures of patient satisfaction will be collected. The proposed research will serve as the basis for future research which will be conducted with dentists in private practice to assess the relationships between dentists' affective behavior, patients' perceptions of their dentist, and the extent to which these behaviors and perceptions influence patients to engage in preventive dental health behaviors, and adhere to treatment regimens.